quench
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What quenches did we observe? What can we expect? Arjan Verweij & Robert Flora on behalf of the MPP, and with the input of many others. Quench. - PowerPoint PPT PresentationTRANSCRIPT
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A. VerweijR. Flora28 Feb 2008
What quenches did we observe? What quenches did we observe?
What can we expect?What can we expect?
Arjan Verweij & Robert Flora Arjan Verweij & Robert Flora
on behalf of the MPP, and with the input of many otherson behalf of the MPP, and with the input of many others
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A. VerweijR. Flora28 Feb 2008 QuenchQuench
Quench: Transition from the superconducting to the normal state
(resulting in a detectable resistive voltage, exceeding the
threshold voltage and discrimination time).
Quench classification:
Heater induced/provoked quench
Natural (training) quench
Secondary quench (due to temperature increase, ramp rate,
etc)
(Beam induced quench)
Circuits with active QPS: we can distinguish converter trip from
natural quench and we have some possibilities for quench
localisation
For circuits that are protected through the power converter (60-
120 A) we are almost blind.
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A. VerweijR. Flora28 Feb 2008
Circuit Nominal current
# circuits # circuits tested towards nominal
# natural quenches
I_q_1/
I_nom
RB 12 kA 1 1 * 3 82%
RQD / RQF 12 kA 2 2 * 1 91%
IPQ (Q4-Q10) 3610-5390 A 13 13 3 90%
IPD (D2-D4) 4400-5520 A 3 3 1 82%
600 A correctors 550 A 46 13 10 63%
undulator 450 A 1 1 3 86%
80-120 A 72 A-100 A 35 12 maybe ?
60 A 55 A 94 92 maybe ?
Natural quenches in 4-5Natural quenches in 4-5
*: nominal not reached
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A. VerweijR. Flora28 Feb 2008
7000
8000
9000
10000
11000
12000
13000
0 20 40 60 80 100 120 140
Magnet number
Cu
rren
t [A
]
4.14
4.73
5.32
5.91
6.50
7.09
7.68
En
erg
y [T
eV]
SM-18: 1st training quenchSM-18: maximum currentQuenches sector 4-5SM-18: 2nd training quench
1 2
3
SM-18: 175 quenches to reach 12 kA in all 154 dipoles
RB circuit: correlation with SM-18RB circuit: correlation with SM-18
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A. VerweijR. Flora28 Feb 2008
9000
9500
10000
10500
11000
11500
12000
12500
13000
0 5 10 15 20 25 30 35 40 45
Magnet number
Cu
rren
t [A
]
SM-18, 1st training quench
SM-18, 2nd training quench
Maximum current SM-18
Quench sector 4-5
SM-18: 39 quenches to reach 12 kA in all 45 quads
RQD/RQF circuits: correlation with SM-18RQD/RQF circuits: correlation with SM-18
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A. VerweijR. Flora28 Feb 2008 IPD’s: correlation with training before IPD’s: correlation with training before
installationinstallation
0
1000
2000
3000
4000
5000
6000
7000
Cu
rren
t [A
]
sector 45: Nominal without quench
sector 45: Quench
Training before tunnel installation
D2L5 D4R4D3R4
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A. VerweijR. Flora28 Feb 2008 IPQ’s at 4.5 K: correlation with training IPQ’s at 4.5 K: correlation with training
before installationbefore installation
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
Cu
rren
t [A
]
sector 45: Nominal without quench
sector 45: Quench
Training before tunnel installation
Q4L5 Q6R4Q5R4Q6L5Q5L5
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A. VerweijR. Flora28 Feb 2008 IPQ’s at 1.9 K: correlation with training IPQ’s at 1.9 K: correlation with training
before installationbefore installation
0
1000
2000
3000
4000
5000
6000
7000
Cu
rren
t [A
]
sector 45: Nominal without quench
sector 45: Quench
Training before tunnel installation
Q7R4 Q10L5Q7L5Q10R4Q8R4 Q9R4 Q8L5 Q9L5
noquench
Training at 4.5 K
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A. VerweijR. Flora28 Feb 2008
Circuits up to 5 TeV 6 TeV 7 TeV
RB 0 ~2 ? (tens)
RQD / RQF 0 ~0 ? (ten(s))
IPQ and IPD 0 ~1 ~4
How many quenches can we expect for How many quenches can we expect for future sectors?future sectors?
Circuits Number of quenches for reaching nominal current
600 A correctors ~35
undulator ~3
80-120 A a few
60 A a few
Numbers are given per sector for all circuits together
This is a rough estimate based on limited experience of sector 4-5 only
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A. VerweijR. Flora28 Feb 2008 RB provoked quench @ 9500 ARB provoked quench @ 9500 A
Cryogenic recovery time: see talk Serge ClaudetCryogenic recovery time: see talk Serge Claudet
LBALA.17R4: 0 s, 9500 A
LBBLA.17R4: 0.2 s, 9481 A
LBBLC.17R4: 33.1 s, 6862 A
LBALB.16R4: 155.0 s, 1886 A
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A. VerweijR. Flora28 Feb 2008 RB natural quench 1 (9789 A)RB natural quench 1 (9789 A)
LBALA.27L5: 0 s, 9789 A
LBBLA.27L5: 62.4 s, 5220 A
LBALB.27L5: 63.1 s, 5181 A
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A. VerweijR. Flora28 Feb 2008 RB natural quench 2 (9859 A)RB natural quench 2 (9859 A)
LBALA.22R4: 0 s, 9859 A
LBBLC.21R4: 126.8 s, 2645 A 381.7 s, 188 A
LBBLA.22R4: 49.7 s, 6013 A
LBALB.22R4: 92.6 s, 3829 A
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A. VerweijR. Flora28 Feb 2008 RB natural quench 3 (10274 A)RB natural quench 3 (10274 A)
LBBLA.27R4: 0 s, 10274 A
LBBLC.27R4: 123.5 s, 2844 A 355.7 s, 238 A
LBALA.27R4: 46.6 s, 6464 ALBALB.26R4: 109.1 s, 3330 A
LBBLA.26R4: 167.4 s, 1748 A
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A. VerweijR. Flora28 Feb 2008 ConclusionConclusion
Experience during HWC of sector 4-5
We experienced about 20 natural quenches, of which 8 in high current circuits
(with quench heaters). This made it possible to make a rough estimate on the
expected number of quenches during HWC of the other sectors.
For all quenches, the detection and resulting actions (heater firing, energy
extraction, PC shut-down) worked perfectly.
‘De-training’ (w.r.t 1st training quench after magnet reception) has been
observed for 5 quenches (2xMB, 1xMQ, D3, Q5L5), and is somewhat worrying.
Quench behaviour with several circuits powered in parallel has not been
tested.
A first estimate on the expected number of quenches during HWC of the other
sectors is made for several energy levels.
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A. VerweijR. Flora28 Feb 2008 ConclusionConclusion
Quench propagation in the RB circuit
MB-to-MB quench propagation time seems to be typically 30-60 s, meaning that
adjacent dipoles will quench at already strongly reduced current (note that 100
s).
2 cases have been observed where the MB-MB propagation time was less than
1 s. The reason for this is under investigation.
2 cases have been observed of MB re-quenching (at low current, after
recovering). For both cases, QPS, heater firing and PM-files generation worked
fine.
Quench propagation from one cryogenic cell to another has not been observed.
The maximum energy dissipated at cold for a quench event has been about 12
MJ, which is about 1% of the total energy in the RB circuit at nominal (1.1 GJ).
Higher quench currents and faster propagation will increase the energy.